Icalendar ICS update not working in google calendar

Question

I have some trouble with the ICS attachment to Gmail/Google calendar addresses. When I have to edit an event I send an update by mail with an ICS file with the same UID of t

Answer 1

see RFC5546 Update an Event

The event is moved to a different time. The combination of the "UID" property (unchanged) and the "SEQUENCE" (bumped to 1) properties indicate the update.

in your case given what you shared you probably need to add a SEQUENCE property in your ical file and increment it for every update you make.

Update: given the ical file you added, you are missing the organiser and attendee fields with below file the update work

BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:pyICSParser
METHOD:REQUEST
BEGIN:VEVENT
DTSTART:20130425T090000
DTEND:20130425T100000
DTSTAMP:20130206T101100
ORGANIZER:mailto:organiser@example.com
ATTENDEE:mailto:attendee@example.com
UID:CALEVENT_TS090519840000000005
DESCRIPTION:test
SUMMARY:test
LOCATION:Test
SEQUENCE:1
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR

Also you need to match the email address of the sender with the one from organiser and same about the attendee, something like below has been validated with google calendar.

eml_as_string:

Subject: New Event
Message-ID: <238497c6d05cffae45716486e74a8009@localhost>
X-Priority: 3
X-Mailer: PHPMailer 5.2.2 (http://code.google.com/a/apache-extras.org/p/phpmailer/)
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="b1_238497c6d05cffae45716486e74a8009"
X-Spam-Rating: mxavas8.ad.aruba.it 1.6.2 0/1000/N

--b1_238497c6d05cffae45716486e74a8009
Content-Type: multipart/alternative;
boundary="b2_238497c6d05cffae45716486e74a8009"

--b2_238497c6d05cffae45716486e74a8009
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit

test

DateTimeRoom
02/05/201309.00 - 10.15ROOM1


--b2_238497c6d05cffae45716486e74a8009
Content-Type: text/html; charset=iso-8859-1
Content-Transfer-Encoding: 8bit











test

    
Date
Time
Room
    
02/05/2013
09.00 - 10.15
ROOM 1







--b2_238497c6d05cffae45716486e74a8009--

--b1_238497c6d05cffae45716486e74a8009
Content-Type: text/calendar; name="event.ics"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="event.ics"

BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:tsCalendar
METHOD:REQUEST
BEGIN:VEVENT
DTSTART:20130502T090000
DTEND:20130502T101000
DTSTAMP:20130209T170100
ORGANIZER:mailto:test@test.eu
ATTENDEE:mailto:test@test.eu
UID:CALEVENT_TS090519840000000013
DESCRIPTION:test
SUMMARY:test
LOCATION:ROOM1 (floor: prova)
SEQUENCE:1
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR


--b1_238497c6d05cffae45716486e74a8009--

on which below script was applied:

# -*- coding:utf-8 -*-
import smtplib
def sendInvite(fro,to,emlasstring):
    mailServer = smtplib.SMTP('smtp.gmail.com', 587)
    mailServer.ehlo()
    mailServer.starttls()
    mailServer.ehlo()
    mailServer.login(login, password)
    mailServer.sendmail(fro, to, emlasstring)
    mailServer.close()

newUID = "UID:newCALEVENT_TS090519840000000016"
#needed to change UID as once an event was sent its UID is locked and a few attempts were needed to make the script work
eml = open("SO14712929_1.eml",'r').read()
emlhead = "To: "+attendee_eml+CRLF
emlhead += "From:"+fro+CRLF
emlhead += "Reply-To: "+fro+CRLF
eml = emlhead+eml
eml = eml.replace("ORGANIZER:mailto:test@test.eu","ORGANIZER:mailto:"+fro_eml)
eml = eml.replace("ATTENDEE:mailto:test@test.eu","ATTENDEE:mailto:"+attendee_eml)
eml = eml.replace("UID:CALEVENT_TS090519840000000013",newUID)
sendInvite(fro,attendees,eml)
print "invite sent"

eml = open("SO14712929_2.eml",'r').read()
emlhead = "To: "+attendee_eml+CRLF
emlhead += "From:"+fro+CRLF
emlhead += "Reply-To: "+fro+CRLF
eml = emlhead+eml
eml = eml.replace("ORGANIZER:mailto:test@test.eu","ORGANIZER:mailto:"+fro_eml)
eml = eml.replace("ATTENDEE:mailto:test@test.eu","ATTENDEE:mailto:"+attendee_eml)
eml = eml.replace("UID:CALEVENT_TS090519840000000013",newUID)
sendInvite(fro,attendees,eml)
print "updated invite sent"